aRTicLe | chemicaL peeLs |
Figure 2 Improvement of pigmentary spots and fine wrinkling on dorsum of the hands in a 60-year-old male. (A) before, and (B) after peel
envelopes were replaced with mature cornified
envelopes 4 weeks after treatment with salicylic acid in polyethylene glycol. Restoration of the photodamaged stratum corneum using this treatment involved the normalisation of keratinocyte differentiation and suppression of skin tumour development14
. The skin lightening effect and nomalisation of
hyperpigmentation by solar lentigines can, in part, be explained by the removal of melanosomes as a result of induced keratinocyte removal. In vitro salicylic acid is a mild inhibitor of oxidation of L-3,4-dihydroxyphenylalanine (L-DOpa) by tyrosinase15 salicylates exert a range of effects on a cellular level.
.
One pathway is the phosphorylation of the eukaryotic translation elongation factor-2 (eiF-2α), and activation of eiF-2α stress-activated protein kinase R-like endoplasmic reticulum kinase (peRK)16
. another pathway is realised
by inactivation of activator protein-1 (ap-1) transcription factor, which results in increased procollagen i, fibrillin-1, and reduced matrix metalloproteinase (mmp)-1 17
. These
molecular mechanisms explain that csa can reduce fine wrinkling by induction of neo-collagenogenesis and reduced collagen destruction by mmp. Derivatives of salicylic acid, especially long-chain fatty
acid conjugates of salicylic acid, have been claimed to be more effective at lower concentrations for skin peeling use18
. a lipophilised ester-derivative of salicylic acid (csa),
Figure 3 Improvement of actinic keratoses and wrinkling in severe UV-radiation damaged skin of a 71-year-old male. (A) before, and (B) after peel
has been shown to be an effective exfoliating agent owing to its reduced penetration in the skin19
. This increases
safety for the patient, diminishing the potential problem of salicylism. it interacts more specifically in the horny layer with corneodesmosin to achieve a precise desquamation, resulting in a thinner and smoother horny layer. The stratum corneum, on the other hand, becomes more resistant to wrinkling and cracking19, 20
.
This results in an improved (i.e. biologically younger) skin barrier function. The ph of csa at 5.5 is close to the ph of normal human
skin. conveniently, csa does not need neutralisation. Desquamation of facial skin can be seen for 1–3 days, but desquamation is much less pronounced when used on the hands. This might be explained by variations of skin barrier lipids, stratum corneum thickness and structure, and water content between facial skin and the dorsum of the hands. in contrast to other peels, csa exerts antioxidant
properties, which can not only inactivate singlet oxygen, but also produce the superoxide scavenger 2,5-dihydroxybenzoic acid (gentisic acid)19
. The
clinical use of csa peels covers different indications, such as acne and acne scars, photodamaged skin, and melasma9, 20, 21
. in this study the author used csa peels to rejuvenate 22 ❚
the dorsum of the hand, and which disclosed a good or better efficacy in all patients (100%) who completed the series of superficial peeling with 10% csa solution twice every month (patient’s global assessment and physician’s global assessment). csa improved the clinical hand assessment by 4–6 score points with an excellent safety profile.
September 2011 |
prime-journal.com
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